The invention relates generally to chaff created to defeat target acquisition. In particular, the invention relates to multiple deflectors of electromagnetic energy away from an intended target.
The concept of chaff goes back as far back as 1937, but not until 1942 was chaff investigated for military use. Typically, aircraft use chaff as a false target to counter against radar-guided missiles. However, chaff can also be used for distress signals so friendly radar can find military platforms that may otherwise have damaged communication systems. Concepts for directed energy weapons have been around for many decades. Incrementally, technology has advanced to a point that the large amounts of energy necessary for directed energy weapons can be stored efficiently and in “relatively” small volumes.
However, directed energy possesses a significant disadvantage of carrying very little momentum and can easily be reflected, or deflected. Electromagnetic waves have very little momentum rendering their reflection or deflection fairly straightforward. For example, the momentum of a projectile that weighs 1 kg can be compared to a light beam that has a micrometer wavelength of 10.6 μm (a typical CO2 laser used to cut steel). Holding the energy constant in both cases to 100 joules (J), the momentum for each case can be calculated.
For the projectile, the velocity, v can be calculated from the energy E and mass, m by formula:
                    v        =                                                            2                ⁢                                                                  ⁢                E                            m                                =                                                                      (                  2                  )                                ⁢                                                      (                                          100                      ⁢                                                                                          ⁢                      J                                        )                                    /                  1                                ⁢                                                                  ⁢                kg                                      =                          14.14              ⁢                                                          ⁢                              m                /                                  s                  .                                                                                        (        1        )            Thus, the momentum for the projectile can be calculated by formula:Pp=m·v=(1 kg)(14.14 m/s)=14.14 N,  (2)where 1 newton (N)=1 kg-m/s. For the light beam, the energy in the laser beam is determined by formula:
                    E        =                              nhc            λ                    .                                    (        3        )            
where h is Planck's constant equals 6.626·10−34 m2-kg/s, c is the speed of light in vacuum, λ is the wavelength of the laser, and n is the number of photons.
The momentum of laser beam photons is determined by formula:
                              P          l                =                              nh            λ                    .                                    (        4        )            The momentum of the laser beam having 100 J of energy can be calculated as:P1=E/c=(100 J)/(3·108·m/s)=3.3·10−7N.  (5)So the momentum of light photon is 3.3·10−7 N versus 14.14 N for the projectile. Thus, the projectile has 4,246,246,246% more momentum than the light beam, even though they both have the same 100 J of energy.
Conventional chaff is designed to scatter electromagnetic radiation from a source to inhibit detection and target acquisition from a hostile adversary. In some cases, conventional chaff can be used to block electromagnetic radiation in the form of obscurants.